Process of and apparatus for transferring heat



Oct 30; I928. 1,689,927

R.-C. NEWHOUSE PROCESS OF AND APPARATUS FOR TRANSFERRING HEAT Filed Dec.14, 1923 L L g a )0 Ai 1 U g "-115 ,L r w 5 3* [8 l I i I f m i 3 I 3Patented oa. 30,1928.

UNITED STATES RAY C. NEWHOUSE, F WAUWATOSA, WISQONSIN.

PROCESS OF AND APPARATUS FOR TRANSFERRING HEAT.

Application filed December 14, 1923, Serial No. $0,578.

This invention: relates in general to improvements in the art of heattransfer, and relates more specifically to an improved method of andapparatus for transferring heat from one fluid such as gases of combustion to another fluid such as water.

A general object of the invention is to provide an improved process ofutilizing hot gases to heat fluid having an initial temperature belowthe dew point temperature of the gases. tion is to provide improved heattransfer apparatus which is especially adapted to effect commercialexploitation of the. improved )5 process, but 'which'is capable ofgeneral application. v

It has heretofore been attempted to utilize gases of combustion derivedfrom various sources, to directly heat liquid suchas boiler :0 feedwater, by. conducting thehot'gases in contact with metal tubes throughwhich the water was caused to flow. It is an established fact that gasesof combustion usually contain in suspension substances such as minutesolid particles, which upon being brought in contact with moist surfacesform a scale or coating and thus prevent eflicient transfer of heatthrough the coated elements. "When the initial temperature of the waterwithin the tubes $0 or prior feed water heaters of this type, was

below the dew point temperature of the gases of combustion whichwerebrought in contact with the tubes, the moisture of the gases wasquickly condensed anddeposited upon the M heat transferring surfacesthus permitting the suspended solids to accumulate in the form of heatinsulating scale. This scale as well as the corrosion produced by themoisture alone, so reduced the efiiciency of these heaters, that itbecame necessary to initially heat the water with the aid of steam, to atemperature above the dew point temperature of thegases, beforeadmitting the water to the heaters. This pre-heatin of the water whilereducing corrosion and coating of the tubes,

is relatively cumbersome and costly.

One of the more specific objects of the pres-' ent invention is toprovide an improved method of and apparatus for utilizing gases ofcombustion containing moisture and scale producing substances, toeconomically and effectively heat liquid having an initial temperaturebelow the dew point temperature of the gases, without danger ofcorrosion of the on heat transferring elements due to deposition Anothergeneral object of the inven-' cation.f The improved apparatus isentirely automatic in operation and has relatively large capacity forrelatively limited space occupied. The improved heaters may bemanufactured at minimum cost, is readily acccssible for inspection andclea-nin and may be conveniently assembled and dismantled. The variouselements of the improved apparatus are subjected only to gradualvariations in temperature and the pressures thereon are substantiallybalanced. These and other ob- 'ects and advantages of the presentinvention will be apparent in the course of the following description.

A clear conceptionof the several stepsof the improved process of heattransfer, and of the details of construction of several embodiments ofthe improved heat transfer apparatus, may be had by referring to thedrawing accompanying and formingpart of this specification, in whichlike reference characters the various vlews.

Fig. 1 is a vertical cross-section through surfaces designate the sameor similar parts in of heat transfer elements, showing the relativedisposition of the gas conducting casing.

Fig. 3 is a diagrammatic disclosure of the improved heater showing therelative loca-. tion of the same with respect to a source of gases ofcombustion.

Fig. 4 is an enlarged fra section through one of the cat transferelements. i

Fig. 5 is an enlarged fragmentary vertical section through another formof heat transfer element.

Fig. 6 is an enlarged fragmentary vertical ment'ary vertical sectionthrough another form of heat transfer element.

Fig. 7 is an enlarged fragmentary vertical section through still anotherform of heat transfer element.

Fig. 8 is a transverse section through the lower portion of the elementshown in section in Fig. 4, the section being taken along the lineVIII-VIII of Fig. 4.

Fig. 9 is a transverse section through the lower portion of the elementshown in section in Fig. 5, the section being taken along the line IX1Xof Fig. 5.

Fig. 10 is a transverse section through the lower portion of the elementshown in section in Fig. (5, the section being taken along the line X-Xof Fig. 6.

Fig. 11 is a transverse section through the lower portion of the elementshown in section in Fig. 7, the section being taken along the line XI-XIof Fig. 7.

The improved heat transfer apparatus comprises in general one or moresections or units each consisting of a plurality of substantiallyparallel tubular heat transfer elements spaced laterally apart andcommunieating with water supply and discharge chambers 8, 10 at one end,and with a settling chamber 11 at the other end. As illustrated in Figs.1 and 2, there are four sections and the heat transfer elements aredisposed vertically, the chambers 8,10 being located above and thesettling chambers 11 being located below the elements. There may howeverbe any desired number of sections or units, depending upon the capacityrequired, and the tubular elements may be disposed otherwise thanvertical. The space surrounding the groups of tubular heat transferelements provides a heating zone 5 confined within a casing l whichcommunicates with a source 15 of hot gases and with a stack 16 as shownin Fi 3. The cold water sup )1 chambers g l y 8 are detachable from theadjacent discharge chambers 10, communicating with a common supplyheader 6 and with the individual heat transfer elements throughdepending pipes 9, see Fig. l. The warm water discharge.

chambers 10 communicate with a common discharge header 7, the headers 6,7 being connected with any suitable sources of cold and warm Waterrespectively. The settling chambers 11 are in open communication withthe lower extremities of the tubular heat transfer elements, and areprovided with cleaning or flush pipes 12 and valves 12' for effectingconvenient removal ofaccumulated solids.

In the embodiment of the invention disclosed in Figs. 1, 2, 4 and 8,each of the tubular heat transfer elements comprises an outercylindrical tube 2 the upper extremity of which is in open communicationwith an ad jacent discharge chamber 10 and the lower extremity of whichis in open communication with an adjacent settlin chamber 11; and aninner downwardly enlarging frusto-coni cal tube 3 the upper extremity12} of which is trumpet shaped and loosely embraces an adjacent coldwater supply pipe 9, and the lower extremity of which rests loosely uponlugs 14 projecting from the lower inner portion of the outer tube 2. Theouter tubes 2 are fixed in position, while the inner tubes 3 are freelyupwardly removable upon removal of the chamber 8 and pipes 9.

In the embodiment of the invention disclosed in Figs. 5 and 9, each ofthe tubular heat transfer elements comprises an outer upwardly enlargingfrusto-conical tube 17 the upper extremity of which is in opencommunication with an adjacent discharge chainber 10 and the lowerextremity of which is in open communication with an adjacent settlingchamber 11; and an inner cylindrical tube 18 the upper extremity 13 ofwhich is trumpet shaped and is adapted to loosely embrace a supply pipe5), and the lower extremity of which rests loosely upon lugs 14projecting inwardly from the inner lower portion of the outer tube 17.

In the embodiment of the invention disclosed in Figs. (5 and 10, each ofthe tubular heat transfer elements comprises an outer upwardly enlargingfrusto-eonieal tube 19 the upper extremity of which is in opencommunication with an adjacent discharge chamber 10 and the lowerextremity of which is in open communication with an adjacent settlingchamber 11; and an inner downwardly enlarging i'ruslo-conical tube 20the upper extremity 13 of which is trumpet shaped and is adapted toloosely embrace a supply pipe 9, and the lower extremity of which restsloosely upon lugs 14 projecting inwardly from the lower inner portion ofthe outer tube 19.

In the embodiment of the invention disclosed in Figs. 7 and 11, each ofthe tubular heat transfer elements comprises an outer cylindrical tube21 the upper extremity of which is in open communication with anadjacent discharge chamber 10 and the lower extremity of which is inopen communication with an adjacent settling chamber 11; and an innerdownwardly enlarging longitudinally corrugated tube 22 the upperextremity 13 of which is trumpet shaped and is adapted to looselyembrace a supply pipe 9, and the lower extremity of which rests looselyupon lugs 14 projecting from the inner lower portion of the outer tube21.

The several forms of heat transi'er elements disclosed in Figs. 4 to 11inclusive, represent only a few of the numerous forms which the improvedapparatus may have, it being desirable however in most cases to avoiddirect contact between the water dclivered from the supply chamber 8 anda wall which is in direct contact with the heating zone 5. The innertubes 3, 18, 20, 22 are preferably always completely surrounded by apro-heated jacket of liquid or other media the temperature of which isat least equal to the dew point temperature of the gases within theheating zone 5.

During normal operation of the improved ap aratus the improved processis automatica ly exploited by producing'a continuous flow of water fromthe header 6 to the inner tubes of the heat transfer elements, throu hthe chambers 8 and depending pipes 9. s the water admitted to the innertubes flows downwardly toward the settling chambers 11, it is graduallyexposed to increasing heat transmitting surface due to enlargement ofthe cross-sectional areas of the inner tubes.

'If the water contains solids in suspension, these will automaticallysettle in the cham-- bers 11, such tendency of the solids to settle[being augmented in cases where the inner tubes are cross-sectionalarea.

Upon reaching the lower extremities of the inner tubes of the heattransfer elements, the flow of the water is reversed from down- Y wardto upward and the liquid passes into the space between the inner andouter tubes. In this space the liquid is exposed to direct transmissionof heat from the gases in the heating zone 5. The upwardly progressingliquid transmits sufiicient heat to the downwardlfi flowing liquid inthe inner tubes, so that t e liquid upon entering the outer tubes hasattained a temperature at least equal to the dew point temperature ofthe gases. The temperature of the'liquid within and without the lowerportion of the inner tubes is substantially equal and the temperature ofthe liquid in the space between the tubes is maintained substantiallyuniform due to the fact that the temperature of the liquid within theinner tubes gradually increases from top to bottom and this liquidtherefore abthe gases st-racts decreasin quantities of heat from thesurrounding jac ets as it proceeds downwardly. I

The liquid delivered from the upper extremities of the outer tubes assesthrough the chambers 10 to the header? and from thence to thesource ofutilization. It will thus be noted that the water admitted from theheader 6 flows gradually through the heater and has its temperatureautomatically increased by being successively indirectly and thendirectly exposed to the hot ases 1n the heating zone 5. Due to the factt at the temperature within the jackets rovidedtby the spaces betweenthe inner and the outer tubes is at all times maintained at least equalto the dew point temperature of the gases passing through the heatingzone 5, the moisture in q is not afforded the opportunity of condensingW relatively cool surfaces, and the suspend solids cannot accumulateupon ing wash formed of gradually enlarging gases through the said gasesthrou' the heat transfer elements in the form of scale.

The settling chambers 11 may be readily cleaned by opening the valves 12and passwater longitudinally through the chambers 11. By removing theupper chambers 8 and the pipes 9, the inner tubes of the heat transferelements are freely vertically removable thus making the entire interiorof the heater accessible for cleaning. When assemblin the heater thetrumpet shaped upper en s 13 of the insertion ofthe pipes 9. Due to thefact that the upper extremities 13 of the inner tubes do not snugly fitthe pipes 9, the pressures upon the substantially equalized. The numberof units comprising the heater may be increased or diminished as desiredand any one or more of these units may be readily replaced. The entireheater may be manufactured at mini-" mum cost and the apparatus isefficient and entirely automatic in operation. I

It should be understood that it is not desired to limit the invention tothe exact steps of the process and to the precise details ofconstruction herein described, for various modifications within thescope of the claims may occur to ersons skilled in the art.

It is ,claime and desired to secure by Letters Patent a 1. The processof utilizing gases of combustion to heat fluid having an initialtemperature below the dew point temperature of the gases, whichcomprises, producing a stream of the fluid having oppositely flowingadjacent portions at least one of which has radually decreasingvelocity, initially raising the temperature of one of said streamportions to at least the dew point temperature of the gases by transferof heat from said other of said stream portions, and subsequentlyheating the fluid from said initially heated stream portion by directtransmission of heat from said gases.

2. The process of utilizing gases of combustion to heat fluid havingan'initial tempera ture below the dew point temperature of the gases,which comprises, producing a stream of fluid having oppositely portionsexposed to heat transfer surface of gradually increasing area, initiallyraising the temperature of one of said stream portions to at least thedew point temperature of the gases by transfer of heat from h the otherof said stream portions, and su sequently heating the fluid from saidinitially heated stream portion by direct'transmission of heat from saidgases.

3. The process of utilizing gases of combustion to heat fluid having aninitial tempera ture below the dew point temperature of the gases, whichcompr ses, producing a streaminner tubes are automatically 7 flowingadjacent inner tubes facilitate increasing area, initially raising thetemperature of said inner portion to at least the dew point temperatureof the gases by transfer of heat from said gases through said outerportion, and subsequently heating the fluid from said inner portion bydirect transmission of heat from said gases.

4. The process of utilizing gases of combustion to heat fluid having aninitial temperature below the dew point temperature of the gases, whichcomprises, producing a stream of fluid having inner and outer oppositelyflowing vertical portions the inner of which flows downwardly and hasgradually decreasing velocity, initially raising the temperature of saidinner stream portion to at least the dew point temperature of the gasesby transfer of heat from said gases through said outer stream portion,simultaneously reversing the flow of the initially heated fluid andremoving impurities therefrom, and subsequently converting the initiallyheated and purified fluid into an outer stream portion and furtherheating the same by direct transmission of heat from said gases.

5. A heat transfer device comprising, vertical tubular members locatedone within the other to provide inner and outer fluid passages, theinner of said passages having gradually downwardly enlargingcross-sectional area and the outer of said passages having graduallyupwardly enlarging cross-sectional area, means forming an enlargedchamber connecting the open lower ends of said passages, means fordelivering cool fluid downwardly through said inner member, means forreceiving heated fluid upwardly from said outer member, and means forconducting heated gas in contact with the outer of said members.

(i. A heat transfer device comprising, vertically disposed tubularmembers located one within the other to provide inner and outer fluidpassages, the inner of said members having gradually downwardlyenlarging cross-sectional area, means forming an enlarged chamberconnecting the lower ends of said passages, means for delivering coolfluid downwardly through said inner member, means for receiving heatedfluid upwardly from said outer member and means for conducting heatedgas in contact with the outer of said members.

In testimony whereof, the signature of the inventor'is allixed hereto.

RAY c. NEWHoUsE.

